In cats, heartworms typically have a shorter lifespan than in dogs.

In cats, heartworms typically have a shorter lifespan than in dogs.

• A. Microfilariae are commonly seen in cat infections
• B. Adult worm burden in cats is higher than in dogs
• C. Dirofilaria causes severe anemia in cats
• D. In cats, heartworms typically have a shorter lifespan than in dogs

Answer: (D)

The main concept here is how long adult heartworms live in cats compared with dogs. In cats, adult Dirofilaria immitis typically survive only a couple of years—roughly 2 to 3 years—whereas in dogs they usually persist longer, often 5 to 7 years. This shorter lifespan in cats helps explain why feline heartworm disease tends to have different patterns than in dogs, including a lower worm burden and more occult infections (fewer or no circulating microfilariae). Because cats often harbor fewer worms and the worms don’t produce as many microfilariae, microfilariae are not commonly seen in cat infections. Severe anemia is not a defining or typical feature of feline heartworm disease, unlike some other parasitic conditions. So, the statement that heartworms have a shorter lifespan in cats is the best, accurate reflection of the differences between feline and canine infections.

The main concept here is how long adult heartworms live in cats compared with dogs. In cats, adult Dirofilaria immitis typically survive only a couple of years—roughly 2 to 3 years—whereas in dogs they usually persist longer, often 5 to 7 years. This shorter lifespan in cats helps explain why feline heartworm disease tends to have different patterns than in dogs, including a lower worm burden and more occult infections (fewer or no circulating microfilariae). Because cats often harbor fewer worms and the worms don’t produce as many microfilariae, microfilariae are not commonly seen in cat infections. Severe anemia is not a defining or typical feature of feline heartworm disease, unlike some other parasitic conditions. So, the statement that heartworms have a shorter lifespan in cats is the best, accurate reflection of the differences between feline and canine infections.